1. Field of the Invention
The present invention relates generally to systems for manufacturing optical components, and particularly to systems and methods for optimizing laser utilization in the writing of fiber gratings and other similar components.
2. Technical Background
A fiber Bragg grating (FBG) is a pattern of regions of increased refractive index permanently written into the core of a single-mode optical fiber. The filters are written by transversely exposing the core to high-power ultraviolet (UV) radiation from a UV laser that has passed through a phasemask to create an interference pattern. The interference pattern causes corresponding structural changes in the core of the fiber, resulting in a permanent and stable modification of the core""s refractive index in predetermined periodic locations.
The writing of an FBG is typically a multi-step process, which includes mounting the fiber into a writing system, connecting the fiber to a measurement system, exposing the fiber to UV radiation, collecting and logging data, and removing the fiber from the writing system for further processing elsewhere. Typical systems for writing an FBG can only process a single fiber at a time. Thus, all of the steps in the writing process must be completed for each FBG before the next FBG can be processed.
Because a laser represents a significant capital outlay, it is desirable for the writing process to be as efficient as possible. In particular, it is desirable for the throughput of the laser-writing system to be increased, without the expense of providing additional lasers. In addition, it is desirable for a single system to be able to process batches of FBGs having different wavelength characteristics without having to reconfigure the system.
One aspect of the invention advantageously provides a system for writing fiber gratings having a plurality of writing stations, each writing station including a fiber mounting fixture for receiving an optical fiber to be exposed to a beam from a laser. The system includes a data capture module for capturing data generated from the exposure of optical fibers in each of the writing stations, and a steering assembly for directing the laser beam to each of the plurality of writing stations in turn.
Another aspect of the invention includes a method for writing fiber gratings by providing writing stations, each including a fiber mounting fixture; providing a steering assembly to direct the laser beam to each station in turn; sequentially mounting fresh optical fiber into the fiber mounting fixtures; exposing the mounted fiber to the laser beam; capturing data for each exposed fiber; and replacing the exposed fibers with fresh optical fiber. The mounting of the fresh optical fiber and the replacement of the exposed fibers with fresh optical fibers at one station is performed while fiber is being exposed to the laser beam at another writing station.
In another aspect, the invention includes a system for writing fiber gratings which includes a beam-shaping optical assembly for shaping a laser beam and a lens for focusing the beam. An array of beamsplitters splits the focused, shaped laser beam into a plurality of sub-beams. This system also includes fiber mounting fixtures. Each lies in the path of a laser sub-beam and has associated therewith a shutter for selectably preventing stray light from entering that fixture.
In another aspect, the invention includes a system for writing fiber gratings that includes an array of mirrors for dividing a laser beam into separate sub-beams. This system also includes an array of beam-shaping optical assemblies corresponding to the plurality of sub-beams. Each beam-shaping optical assembly shapes a respective sub-beam. An array of fiber mounting fixtures corresponding to the array of beam-shaping optical assemblies has each fiber-mounting fixture in the array positioned to receive a shaped laser sub-beam. Each fiber-mounting fixture has associated with it a shutter for selectably preventing stray light from entering that fiber-mounting fixture.
In another aspect, the invention includes a system for exposing optical fibers to a laser beam, including exposure stations, each of which includes a fiber mounting fixture for receiving an optical fiber to be exposed to a laser beam. A data capture module captures data generated from the exposure of optical fibers in each of the stations. A steering assembly directs the laser beam to each of the stations in turn.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operation of the invention.